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SQL – Find total number of orders made for each customer

I have 2 tables customer and orders. Each customer can place multiple orders

  • customer has a column customer_num
  • orders has columns order_num, customer_num

I want the results to show like this:

enter image description here

Here is my current code which only returns all the distinct customer num

select distinct c.customer_num  
from customer c 
inner join orders o on o.CUSTOMER_NUM = c.customer_num

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Answer

Try the below – using count() aggregation with group by

select c.customer_num,count(order_num) 
from customer c inner join orders o on  o.CUSTOMER_NUM = c.customer_num
group by c.customer_num
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